6.
(1) The standard value applicable to any class of livestock shall be –
(a) in the case of any farmer (other than a company or the estate of a deceased person) who on or after the first day of July, 1955, and before the first day of July, 1962, rendered returns of income in respect of farming operations, the standard value which in relation to such farmer applied to that class of livestock in accordance with the provisions of paragraph 13 of the Third Schedule to the Income Tax Act, 1941;
(b) in the case of any other farmer (other than a company or the estate of a deceased person) or in the case of any farmer (other than a company or the estate of a deceased person) who on or after 1 July 1962 includes that class of livestock in his return of income for the first time, either –
(i) such standard value as may be fixed for that class of livestock by regulation made under this Act; or
(ii) such other standard value as the farmer may, subject to the provisions of subparagraphs (2) and (3), adopt for that class of livestock when rendering his return of income on or after the said date in respect of farming operations, or when so including in any return of income such a class of livestock for the first time;
(c) in the case of any company or estate of a deceased person the return of income of which in respect of farming operations for the first year of assessment of that company or estate ending on or after 1 January 1977 includes that class of livestock, either –
(i) such standard value as may be fixed for that class of livestock by regulation made under this Act; or
(ii) such other standard value as such company or the executor of such estate, as the case may be, may, subject to the provisions of subparagraphs (2) and (3), adopt for that class of livestock when rendering the said return of income;
(d) in the case of any company or estate of a deceased person the return of income of which in respect of farming operations for a year of assessment subsequent to the year of assessment referred to in item (c), includes that class of livestock for the first time, either –
(i) such standard value as may be fixed for that class of livestock by regulation made under this Act; or
(ii) such other standard value as such company or the executor of such estate, as the case may be, may subject to the provisions of subparagraphs (2) and (3), adopt for that class of livestock when rendering the said return of income.
(2) No standard value adopted under subparagraph (1) (b) (ii), (1) (c) (ii) or (1) (d) (ii) in respect of any class of livestock shall be more than twenty per cent higher or lower than the standard value fixed by regulation under this Act in respect of livestock of that class.
(3) Any farmer who classifies any kind of his livestock on a basis other than that applied by a regulation referred to in subparagraph (1) (b) (i), (1) (c) (i) or (1) (d) (i), may adopt in respect of any class into which he so classifies that livestock such a standard value as may be approved by the Commissioner with due regard to the values fixed by regulation.